All‐Oxide Transparent Vertical Indium Tin Oxide and Aluminum‐Doped Zinc Oxide/β‐Ga2O3 Schottky Diodes

Abstract

Herein, the fabrication and characterization of low‐resistance all‐oxide transparent vertical β‐Ga2O3 diodes using indium tin oxide (ITO) and aluminum‐doped zinc oxide (AZO) Schottky contacts are reported. It is shown that an ITO ohmic contact to n+‐β‐Ga2O3 substrate is formed after annealing in N2 at 800 °C. Both AZO‐ and ITO‐based Schottky diodes show well‐behaved current–voltage characteristics. Average Schottky barrier heights and ideality factors are 0.99 and 1.05 eV and 0.95 and 1.03 eV for AZO and ITO Schottky contacts, respectively. The on‐off current ratio is about 2 ×$\times$ 1010 and 1 ×$\times$ 1010 for AZO and ITO Schottky contact, respectively. Moreover, the on‐state resistance is about 6–7 and 4–5 mΩ cm2 for AZO and ITO Schottky contact, respectively, and is 20–35 times lower than for previously reported transparent β‐Ga2O3 Schottky diodes.